It has been stated, as for example in prior art U.S. Pat. No. 3,337,776, a variable or continuous magnetic field can have beneficial biomedical applications. Other examples than the therapeutical purposes of this patent were also noted in the prior art. More particularly, in the promoting of the healing of bone fractures there are prior art U.S. Pats. 3,890,953 and 3,915,151. Also noted was U.S. Pat. No. 3,358,676 which is suggestive of means for producing a varying magnetic field that will act on an element introduced to a vascular system to impart thereto a vibrational or rotational motion such that propulsion is effected by contact with the vascular system.